Compare 181 vs 187
| Property | 181 | 187 |
|---|---|---|
| Type | prime | semiprime |
| Unique factors | 1 | 2 |
| Total factors | 1 | 2 |
| Prime factorization | 1811 | 111 × 171 |
| Prime factorization | 181 | 11 × 17 |
| Divisors count | 2 | 4 |
| Divisors | 1, 181 | 1, 11, 17, 187 |
| Number of properties | 8 | 1 |
| Centered square primes | 6th | |
| Chen primes | 33rd | |
| Dihedral primes | 5th | |
| Long primes | 16th | |
| Palindromic primes | 9th | |
| Primes | 42nd | |
| Pythagorean primes | 19th | |
| Semiprimes | 61st | |
| Twin primes (2nd member) | 13th | |
| Roman numberals | CLXXXI | CLXXXVII |
| Base 2 | 101101012 | 101110112 |
| Base 3 | 202013 | 202213 |
| Base 4 | 23114 | 23234 |
| Base 5 | 12115 | 12225 |
| Base 6 | 5016 | 5116 |
| Base 7 | 3467 | 3557 |
| Base 8 | 2658 | 2738 |
| Base 9 | 2219 | 2279 |
| Base 10 | 18110 | 18710 |
| Base 11 | 15511 | 16011 |
| Base 12 | 13112 | 13712 |
| Base 13 | 10c13 | 11513 |
| Base 14 | cd14 | d514 |
| Base 15 | c115 | c715 |
| Base 16 | b516 | bb16 |